Method and means for centerless grinding without propping of work by abrading surface



2,544,318 ITHOUT W. HORBERG AND MEANS FOR CENTERLESS GRINDING W PROPPING OF WORK BY ABRADING SURFACE March 6, 1951 METHOD 7 Sheets-Sheet 1 Filed Sept. 11, 1946 ATTORNEY March 'w. HOR BERG METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE 7 Sheets-Sheet 2 Filed Sept. 11, 1946 INVENTOR ATTORNEY March 6, 1951 w, ORBER 2,544,318

METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE Filed Sept. 11, 1946 7 Sheets-Sheet s ATTOR N EY March 6, 1951 w. HORBERG 2,544,318

METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE Filed Sept. 11, 1946 7 Sheets5heet 4 4 38 ATTORNEY 2,544,318 METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE Filed Sept. 11, 1946 W. HORBERG March 6, 1951 7 Sheets-Sheet 5 ATTORNEY INVENTOR March 6, 1951 I w. HORBERG 2,544,318

METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE '7 Sheefcs-Sheet 6 Filed Sept. 11, 1946 4 I 0 4 3 T W Mm r v I INVENTOR ATTORNEY w. HORBERG 2,544,318 METHOD AND MEANS FOR CENTERLESS GRINDING WITHOUT March 6, 1951 PROPPING OF WORK BY ABRADING SURFACE '7 Sheets-Sheet 7 Filed Sept. 11, 1946 /7/ niiiv ATTORNEY i atented Mar. 6, i95i METHOD AND FORI-CENTERLESS GRINDING WITHOUT PROPPING OF WORK BY ABRADING SURFACE William Horberg, Bridgeport, Conn. Application September 11, 1946, Serial No. 696,308

' Claims: (01. si ma This invention relates to grinding and particularly to methods and machines for performing centerless grinding wherein the grinding wheel or other fast movin abrasive surface is not employed to assist in the centerless support of the work piece that is being ground.

In the conventional practice of centerless. grinding a workpiece is rotated usually on a horlzontal axis while supported solely by means of itsperiphery. The means of support commonly consists of three elements-t-he grinding wheel which scrapesin contact with one side of the work piece, an opposed frictional or work con-- trol wheel which clingingly rolls in contact with theother side of the work piece and a stationary underlying support on which the bottom peripheral'surface of the work piece bears while rotating. .These three element form a constrain-;

ing'1 channel which may be referred to as the grinding throat of a conventional centerless grinding machine in which throat the work piece is nested while being rotated by the control wheel andultimately ground to size. The ultimate size is determined by the narrowest dimension, of the. space or gap between the grinding wheel and the control wheel to which the work piece is permitted to sink by the underlying stationary rest or work support.- Obviously under these conventional conditions if a peripheral contour is to be imparted to the work piece other than that of an all-cylindrical or'all-conical shape, such can be accomplished only by correspondingly shap-' ing the abrading surface "of the grinding wheel, whereas profiling the terminal end of the work piece to various crowned'shapes can not bedone at all in a conventional grinding machine.

i There is alarge range of work which hereto fore has been ground in ordinary centerless grinding machines consisting of relatively slender and elongated rods- 01' spindle-like work pieces,-

manyworkpieces of this character having stepped diameters and irregular profile shapes andrequi'ring grinding to accurate shapes and sizes at -or near both ends as well as in various the art of centerless ing thereof. Consequently the rate of production and degree of accuracy of shaping and sizing which it has heretofore been possible to accomplish by centerless grinding have fallen far short of the resultant efiiciency demanded by modern production standards.

My present invention successfully overcomes the above explained disadvantages of those prac-' tices which have prevailed in the centerless. grinding art. It aims to retain the well understood operative benefits of centerless grinding while greatly speeding up and increasin the accuracy of output of centerless ground work, and' especially of slender, spindle-like pieces.

A contributory object is to avoid dependence on the rotating grinding wheel to serve as the lateral abutment against which the work piece is urged by the rolling thrust of the work driving frictional or control wheel. Attainment of this object leaves the work piece .free to be maneuvered bodily in chosen angular relationships to the grinding wheel while it is being rotated on its own longitudinal axis by thecontrol wheel. A related object is to provide a centerless support for a rotating work piece confined to carrier structure that is free to be maneuvered bodily for presenting selectively different surfaces of the'work piece to the grinding wheel. A contributory object is to include in such centerless support a work driving or frictional control wheel driven by a flexible shaft from a source of power stationed apart from the work carrying structure.

sections of their length. Not only are conven v tional centerless grinding machines wholly incapable of profiling the end of such work pieces in a manner to produce desired varieties of rounded, beveled, "orflat end shapes but cent-erless grinding machines. as heretofore, known are far more heavy and cumbersome in relation to the size and :weightof such slender, spindle-like work pieces thanisnecessary for the requisite firmness of work support during centerless grind-1 "A further object is to constrain a carrier affording centerless means of support for the work piece'ina manner to restrict and in part prede-.- termine the permissible paths in which it can manually be maneuvered.

A further object is to facilitate placement of the work piece on its means of centerlesssup-: port as well as removal of the work piece there-: from.

A further object is to avoid the necessity of feeding small work pieces toward a grinding wheel by means of bodily moving a heavy, cumbersome and hard to budge bearing frame structure in which the work driving-frictional or con-- trol wheel is journaled in conventional centerless grindingpractice. l

A further object is to makeuse of a furcate rest for supporting the work piece near its surface which is to be presented to the grinding wheel,

'A related object is to arrange plural work control wheels so acting on one section of the length.

3 of a single work piece that an outboard section of said length is biased by the control wheels in a predetermined lateral direction against the aforesaid furcate rest while the work piece is being rotated by the control wheels.

A further object is to provide stop means predetermining positively the endwi se placement or the Work piece 'on its centerless support carrier so that the location of the carrier in relation to a grinding Wheel in directions lengthwise of the work piece can accurately determine the length to which the work piece will be ground bythe grinding Wheel.

A related object is so to skew the work control wheels that they will constantly urge the work piece endwise against the aforesaidstop means while the control wheels are causing thev work; piece to rotate.

The foregoing and other objects of the invention are obtainable by practices and mechanism r'wmc illustrative examples are explained in the following description having reference to the appended drawings wherein;

' Fi g. l is a'perspective view of a complete grinding machine incorporating improved apparatus for practicing my new method of center-less 'r i l t s ra i of bigfiligs e a ds Figl 1 ws' 's a setni cf sam sara us' as 1 arran d fa c ndr cal an taps-f g i n owed-1 g w r pieces;

F o s ap aratu 9 modifies. ceaiiu n. sat up?! rind fl was 9. qn ated. Work Pieces j m n r t ra ual accurate engths, fthe at c F 4 s. an is metri cxp 'cdcd view or a, two; p an tt e f. won; arri s i l ievsii. i'r i' t g in in m ch ne Fi s. 1 and;

'Fi 5 is a an vi h wqrk. carr er o i e- 4 cqm c s smb l with w rk. see. T m e g 6 a i he h l. n c hs WQ TK a g? i n f m. e i vard F Fi s is a e i t w cndof. the wo k carri r ckin f om me r h tq z' 'ard F Fig. 8 is a view taken in section on the "planes 3- in Fi 5 l ck in. ac'qir ti a of as a M r n. on n nlar d s ale .1 si asuitable. for actual structure.

Fig. 9 is an enlarged detached isometric View exposing the work rest blad 'of Fig.4.

Fig. 10 is a viewlake i b i ftial y in cent al lengthwise sectio n't hrou'g h' the speed reduction angle unit of Figs. 1, 2 and 3, as on the plane l0- f0 ihFig. 5 0r1'11 l Fig. 11 is a plan view of amodifiecl or three: wheel planchette type of i work' 'carrier remi d from the grinding machine of Fig.3

Fig. 12 is a view taken in section on the plane I2I2 Fig. l1, looking in' the direction-oi the arrows showing the parts on an enlargedscale suitable in size for actual use onwork of-"common sizes. Fig. 13 shows a set-up of the three wheel work carrier of Fig. 3 specially equipped with a; base fixture enabling the work to be swung toward and away from the grinding wheel about a stationary horizontal axis.

Fig. 14 is an enlarged perspective view of the base fixture of Fig. 13 with most or the work carrier parts omitted.-

' Fig. 15 is a side elevation of' the base fixtureof Fig-.14.

Fig. 16 is an end view. of the same ba e fixture looking from the right at Fig. 15'.

The grinding machine As the present invention is concerned more particularly with apparatus for bodily maneuvering the work in relation to a power driven abrasive surface in a grinding machine and for peripherally supporting a rotating work piece W thc ns ra n sis anc b 53 ab surface, there is shown only sketohily herein a power driven abrasive surface I3 embodied as the peripheral face of a grinding wheel I2 whose horizontal power shaft I4 is journaled in suitable hearings I5. These shaft bearings are part of a turrethead I5 that is mounted to be turned about'a vertical axis on the bed I! of a grinding machine of the surface grinder type. Turret head I6 can be fastened in any selective position to which it may beturned by tightening suitable clamp bolts such as I8 that extend through segmental slots such as I9 in a base flange 24 of the turret head, bolts I8 having threaded engagement with the machine bed IT.

The grinding wheel shaft M has fixed thereon a belted pulley 20' (see Fig. 2) driven from a line shaft, or if preferred from a direct connected power motor fast to the frame of the machine. The grinding machine-may also be equipped with any conventional attachment 2| for dressing the grinding wheel. Also. as is conventional in grinding machines, a. liquid coolant is pumped, through pipe line 22' and out ofa discharge, nozzle 23 against the abrasive surface] I3 of grinding wheel I2.

On frame H of the grinding machine there is. mounted" a table 30' slidable. onways: 3 I by meansof feed screw 32 turned by operating handle 33. to push and pull table 30 along ways 3I relative. to'grinding wheel I2. Feed screw 32 also serves; to hold table 30 in selected positions in which it may be set. For fastening table 30- even more fixedly to its Ways 3I conventional clamp. gibs; releasably tightened by set screws in the usualmanner may be employed. Such are not herein illustrated becausefor many of the purposes of the. present invention table 30 remains station-. ary with frame ll. of the grinding machine.

Q flcring types. .1? work ca r ers The top, surface,- 39' oftable; 30 serves as a 31231: tionary platform on which; rests, and with respect, to. which is. maneuvered, various; work; piece ca riers.v characterized y the, f atu es o t is my t on nclud n the: feature. hat. h Wor R c carrier is, bodily movable.- as. a who e; re a on to; the: pow r; driv n abrasive surfac or ri ng wheel face I3 wh leit supportsthe. warpiec -and causes, it, to. rotate. Gonstraint: and; rptatiomoi. the workpieceis; accomp ishedby-mcanso a et or work control: Wheelsrotatably mounted on the bodily. mov ble work carrier-and rra sed'bo rn; in per pheral rollin c n act, with p site; s des or the circular; work. piece simultaneously.

In all forms of my i pr ved. wor arr er herein illustrated atv least, one, of the wheels of the said. set'ijs power driven, and transmits, its, rotarypower drive by friction to the work piece, v and there, are, worksupporting. means. below; the. levels of peripheral contact of; two of the afore: said wheels with the work piece. Such WQFkSllIJr. porting: means may. comprise; a stationary Work; restor anadditionab wheel or roller that, underv 'lies and bears the weight; of: the rotating-work piece. ina manner thatv determines the. height, level at which the. work piecewill be. maintained while his being rotated on its. bodily movable carrier.

with an adjustably positioned stop arranged .to'

take the endwise thrust of the work piece in a direction away from Such furcate rest.

The foregoing and associated features of my improved work rotating carrier will now be de-' scribed. in several particular forms of mechanism in which they may be incorporated according to the constructions herein illustrated.v For brevity these different forms of carrier may be classed as of the two-wheel or three-wheel type according to their means for constraining and rotating the work, and as of planchette or swingable types according to their manner of'bodily maneuvering the work. Of the swingable types. there is herein illustrated one carrier (Fig.12) which swings lon'a vertical axis and another carrier' (Fig. 13) which swings'on a horizontal axis. All types embody' my present .improvements in the art of centerless grinding wherein a work piece is ground to true roundness and perfect size by centerless grinding principles without depending on the surface of the grinding wheel to assist in the constraint of the work or to prede-.1 termine its finished size.

Construction of two-wheel planchette work carrier --In Fig. 1, this form of work carrier is shown setup for use in profiling the end of a circular work piece 61 of elongated, slender or spindlelike nature. Construction of its details appears more clearly in Figs. 4 to 8, inclusive. See also Fig.2 and Fig. 11. In this carrier there are only two wheels in the set of wheels which roll simultaneously against the periphery of the work piece. One of these wheels 4| is removably fixed 'on a stub shaft 42 that is journaled within the tubular extension 43 of a housing 44 for a portable power transmission unit 45 of the angle type- Within housing 44, as best shown in Fig. l a worm wheel 45 is keyed to shaft 42 and in mesh with a driving worm 41 whose spindle 48 has roller bearings 49 and 50 in housing 44 and is flatted at to, be drivably coupled to a flexible power shaft 52 '(see Fig. 5). Shaft 52 extends throughout the length of a flexible conduit 53 and connects to the shaft 51 of pulley 59 in the variable speed power unit 58. One end of conduit 53 is anchored to the bearing structurev 63 for shaft 51 while its other end is anchored to the housing 44 of a speed reduction unit hereinafter described.

Unit 58 may take any of numerous forms. For convenience of illustration it is herein shown to comprise two reversely stepped pulleys 59 and 60 the former of which is coupled to the flexible shaft 52 and the latter of which is fast on the shaft 6| of motor 62. The bearing structure 63 for shafts 52 and BI is adjustably supported by an upright frame post 64 whose base may stand on the floor at the side of grinding machine IT, or whose base, as appears at 65, may rest on the bed I! of the grinding machine. The present inyention is not particularly concerned with the exact construction nor the location of the variable speed unit 58. In some cases it might to advantage be located overhead like a line shaft in the near neighborhood of the grinding machine. It is highly desirable, however, that the source of motive power for driving wheel 4| shall not constitute a load burdening my improved work carrier with its weightnor imparting to 6 suchcarrier the'ip'erlodic vibrations of electric motor 62, and of theqiulley connecting: belt 66.? Such burden of weight woulddestroyjthe sensi-. tivity with which the work carrier as awhole,' could be bodily moved and such vibrations would interfere with smooth true concentricrotation: of workpiece 61. .Also the drawings show. the. importance to free and random roving mobility of the work carrier that the shaft 52 and its con-.

duit 53 be long enough and so disposed as to eX-b tend downward into operatively c'oupled;-rela'-' tionship' to transmission unit 45. I have further-J discoveredthat in transmitting driving power to, one or moreof the. wheels of my improved work;- carryin'g apparatusit considerably relieves any tendency to ierkiness, arising from the perform-i ance of flexible'shaftw52 or looseness inv its .connections, if such :shaft is driven at high speed rather than low speed, in its conduit 53. This calls for the speed reducing function of transmission unit 45 to be performed at the work carrier'end'of shaft 52 rather than at its power; source end. In Fig. 4, wheel 4| together with the housing 44 of power transmission 45 is shownremoved from its working position in the planchette work carrier in order better to expose the other work piece supporting and constraining elements. These elements include the presser wheel 12 and the underlying stationary supporting'blade whose flat top edge serves as work .rest 13. (See also Fig. 9.) i v In Figs. 4 to 8, inclusive, it will be clear that in normal use the tubular housing extension 43 of transmission 45 is firmly clamped in stationary working position within a split bearing 14 whose lateral cap piece 15 is removable by loosening clamp bolts 18 having threaded engagement therewith. 'Bolts 16 pass through clearance holes in the bearing bracket 11 which itself can swivel about the axis of a clamp bolt 18 that has threaded engagement therewith and passes through a clearance hole in the frame bracket 19 of this two-wheel, planchette type of carrier;- When clamp bolt 18 is tightened the split bearing 14 and hence the work driving wheel 4| is bodily stationed with its axis of rotation disposed at any chosen angle of deviation from true hori-. zontal disposition that will cause work drive wheel 4| 'to be slightly skewed in a direction serving constantly tourge work piece 6'! axially endwise against a fixed adjustable stop rod 80. The work contacting end of the rod may be crowned or pointed to reduce the friction between it and the work piece. 1-

Stop" also takes any endwise thrust by the grindin wheel upon the work piece in directions lengthwise of the work piece. Stop rod 80 is supported in and longitudinally adjustable in a hole in the top portion of a vertically adjustable post 82 being releasably fastened therein by a set screw 83. Post'82 is itself fastenable in chosen vertical positions in a groove in its standard 84 by means of a clamp screw passing through an elongated slot 10 in standard 84 and having threaded engagement with post 82. The angle base of standard 84 contains a transversely elongated slot 68 through which passes a holding bolt 89 having threaded engagement with a saddle slide |ll2 so that standard 84 while adjustably mounted on slide I02 can also be shifted with the latter lengthwise of the main frame bar 91 of the work carrier. A gib I03 and screws 14 fas ten slide I02. The other or presser wheel 12 may have roller hearings in a rocker sub-frame -wh1ch includes a'tilting base 86 in rigid relation to an upstanding bearing bracket 81 in which the trunnion shaft 88 of idler wheel 12 is given plain or roller bearings with suitable thrust means to. keep idler wheel 12 from axial movement. Figs. 4, 6, 8 and 9 show that sub-frame base 86 has downward extending flanges 89 which are swingably supported by hinge bolts 9|] passing through clearance holes in the .fianges 89 respectively and having threaded engagement with a frame block 9| against which the bottom end of an adjustable stop screw 92 abuts to limit the clockwise tilting of sub-frame base 86 inFig. 8 if the work piece 61 is absent. Stop screw 92 may be locked in any set position by the lock nut 93, and threads into tilting base 86.

An arm 96 is fixed on sub-frame 86 and extends crosswise of the frame'bar 91'which serves as the backbone of the carrier frame and supports the aforesaid frame block 9| and. frame bracket 19 in fixed relation to each other. This arm terminates in a flattened handle 95 and is urged downward by a spring 94 stretched between said arm and a stationary spring anchorage bracket 94' fixed on frame bracket 19 as best shown in Fig. 6. A finger rest 8| is also fixedly secured on frame bracket 19 for use cooperatively with handle 95 as indicated in Fig. 6 and hereinafter further referred to.

The work rest blade 13, as best shown in Figs. 4, 8 and 9, may be fixedly clamped at chosen heights in a groove in its split holding block 98 whose separable sections are drawn together by the clamp screws 99 and which as a whole is kept rigid with the frame block 9| by holding screws IIl'Il passing therethrough and having threaded engagement with holes in the edge of block 91. Thus the work rest blade 13 occupies a vertically adjustable position directly beneath work piece 61. The periphery of the rotatin work piece rests on the top flat edge of this blade while the work piece is being rotated by its rollin contact with work control wheels II and 12. Presser wheel 12 can be swung retractably away from the work piece (counterclockwise in Fig. 8)

by manually lifting handle 95 against the resistance of spring'94 to the position shown in broken lines in Fig. 6.

The foregoing means of support and means of rotary drive for the work piece is comparable to conventional centerless grinding practice with the exception that the presser wheel 12 in constraining the work piece, serves what has formerly been a propping function of the grinding wheel in conventional center-less grinding.

In this improved'practice of centerless grinding, the remote or toe end of the work piece which is in outboard relation to the work control wheels II and 12 rests in a furcate upstanding guide plate I near a portion of the length of the work piece that is to be'brought against the grinding wheel. Guide plate H9 is an abutment presenting to one side of the work piece a vertical constraining face or notch edge III and to the opposite side of the work piece an-roblique or sloping notch edge I12. Guide plate IHI also is shiftable to chosen vertical positions in the ,groove of an upstanding arm of holding bracket 4 I3 to which it is made fast by the clamp screw ,I which passes "through an elongated slot .I I6 in bracket H3 (see Fig. 7=) and threads into guide plate 410. The base branch of bracket II3 contains a transversely elongated slot 445 through whichpasses a holding screw :-I I1 havin: threa ed neaee m with the. saddle "slide H8 that seats snugly on and is shiftable lengthwise of the frame bar 91 of the carrier, being fastenable thereto by set screw H9. vvA gib I26 clamped by screw II9 fastens slide II8 to frame bar 91. 7

Frame bar 91 is given three-point, gliding support by two front legs I25, I26 and one rear leg I21. Front legs I25. I26 are made adjustably rigid with frame bar 91 at chosen stations along its length by means of a cross bar I29 grooved to, receive and fit the frame bar 91 and fastenable thereto by a gib I3I and set screw I30. .Each, of the legs I25, I26 is screwed tightly into bar I29 .while leg [21 is tightly screwed directly into the frame bar 91. While this three-legged support of the carrier enables it to rest stably on the top surface 34 of table 30 it enables. the car-.- rier as a. whole tobe slidable freely along said surface. in random directions to arbitrary poshtions. From this characteristic of mobility the carrier derives its name planchette. More than three-point support can be provided to en-.. able the carrier to glide freely about on table surface 34 within the novel principles of this in-- vention.

The planchette type of two-wheel carrier of Figs. 1, 2 and 4 to 10, inclusive, is further equipped with a carrier manipulatin and steer ing handle I35 that is rigid with and upstands from cross bar I 29. For profiling the ends of rod-like or spindle-like work pieces a pilot or pattern contour toe I36 is fixed at the end of the frame bar 91 nearest the grinding wheel. 'This pattern toe is located as best shown in Figs. 1.

4 and 5 to meet and rock against a rigid up standing work sizing plate I31 that is rigid with the grinding machine table 30 and hence normally fixed in relation to the bodily position of grinding wheel I2. While the convex pilot edge of pattern toe I36 is shown to have a circular curvature whose diameter parallel with the axis of the work piece 61 is offset laterally from such axis, it is more often desirable to have the diameter of circular pattern curvature in a common vertical plane with the axis of the work piece and therebelow.

Operation of. pattern controlled two-wheel planchette carrier 4 I Referring particularly to Fig. l the two-wheel planchette carrier of Figs. 4 to 9, inclusive, is shown resting upon and free to glide in random directions to arbitrary positions with respect to the abrasive face I3 of grinding wheel I2, while it supports and rotates the work piece 61. Whereas the speed reduction unitAB is shown at the heel end of the carrier in Fig. 1 this speed reduction unit in Fig. 5 is shown to be located nearer the toe end ofthe carrier. This need not afiect the operation of the work control wheels but merely illustrates that the positioning of. the speed reduction may be shifted to either of these locations owing to the ability of bracket 11 to swivel through a half circle about the axis of its clamp bolt 18. When bracket 1'! is positioned as'in Figs. 1 and 2, the notch I05 accommodates handle lever 95..

Assuming that a crown end is to be ground .on-work piece 61 in three dimensional conformity with the two-dimensional convex pattern edge J38 of the pattern toe I36, the operator will grasp handles 8| and as shown in Fig. 6 and retract presser wheel 12 to its broken line position in Fig. -6 by lifting .on handle 95 thereby to make room fonlaYiBd the workpiece 61 on the workirest gter-n edge I38 in a three-dimensional form of a work because the work piece itself is rapidly be- :ing rotated by. a power source that-is independ- ....ent of the grinding wheel. At the same time an finishe w rk ir ege be au e. it. sewer 51-3- between controlwheels 4i and 12.- In doing -.this the operator with his right hand will thrust .the work piece endwise against stop 8t and will lay a truly round end section of the work piece near its'surface that is to be ground within the ,notch of furcate guide plate H in outboardree lation to the control throat of the carrier formed by rest [3 and control wheels 4|, 42 Then the work piece is without support or interference with its desired concentricity of rotation at any point v between the aforesaid control throat and the guide plate I I0. Upon releasing'handle 95, spring 94 causes the presser wheel 12 to thrust work piece 61 against the driving wheel 4! and slightly :downward against the stationary;rest l3. latter is adjusted to a verticalheight such that its center is preferably no higher than the center of rotation of at least onev of the control wheels 4! and 12. Stop screw 92 will. be observed wheel 12 against the, work piece. However, in the absence of the .work piece this screw will come into play to prevent contact between wheel 12 and the edge of work rest 13. 7 With the work piece 61 supported jointly by; the control throat of the carrier and guide plate .i.l.|0, the power driven rotation of the work driv- '.'ing wheel 4|. will impart high speed rotation to the work piece 61 and at the same time will exert a componentof force on the work piece r; -l'engthwise thereof toward stop 80 because of the skewed dispositionof, wheel 4! clearly shown in Fig. 5. If desired, wheel I46 may. be correspond- .ingly vskewed to. 1 ztfating work piece against stop 80. .is also to be observed that wheel 4| preferably strengthenthe urge of. the ro- In Fi '5' it;

;.bears laterallyagainstthe periphery of: .th'e work .piece at pointsat..least partially offset i n an '.axial direction toward. .the toe end of the.--cartrier with respect to-presser wheel 12'. con-g stantly biase's'the end of the work piece that rests in guide plate Hi1 against the vertical edge (LII of the notch in such guide plate while the "work piece is rotating. The workpiece 61 is thus urged by the cooperative action of control f'wheels 4i and 12 downward against both the rest .13, and "sidewise against the vertical edge Ill tof'the'notch in the :guide plate I lllpas well as rearward against stop 80.

With the work piece so supported and in rapid rotation, the operator may easily grasp steering ihandle I with his right hand and may grasp .-"any convenient portion ofthe heel end of the scarrier with his left hand and under the control .r of both hands shove. the carrier bodily about the table surface 34 in random directions to and retf rom, as well-"asjacross, the face [3 of *the grind- .z'ing wheel. However, the proximity of the car- *zrier to the grinding wheel is, limited and prede- :ftermined in all angular dispositionsbythe abut- '.ting.:ofpattern edge :i38jof pattern toe 136 against -the-istationary' work sizing or baflle plate I313.

Hence if this toe of the carrier is thrust toward the grinding wheel as far as plate I38 permits 1-.;.while the heel end of the carrier is swung from left to right and vice versa in Fig. 1, the grindi.. .1.g, wheel will impart to the endnf the work .Jgiece a crowned contour or a profile shape that -,duplicates the two-dimensional curvature of pat- ;sxact desired overall length will be produced in mains in endwise contact with stop 80 and the distance from the latter topattern toe edge I38 l 'is 'anadjustable constant.

' Operation of pivot anchored two-wheel I Y swinging carrier In Fig. 2, the same two-wheel planchette or gliding carrier is shown as is shown in Figs. 1 and 4 to 9, inclusive. In Fig. 2, however, the single'carrier leg I21 near the heel end of the carrier is'rotatably journaled in a vertical bearing hole:l 33 in the pivot block I32 that isma'de fasttothe tablesurface 34. This permits the The 9:

jcarrijer to glide about on table surface 34'asi'n Fig. '1; except that all parts of the carrier,-to-

, gether. with its carried work piece, are constrained tOf move: solely in circular paths about the verti- ;.in Fig. 8 not to interfere with the pressing of 2 calaxis of leg I21.

the 'work piece control throat of the carrier but This more or less stations permits those portions of the work piece that are in outboard relation to such grinding throat to be swung toward and away from the abrading surface I3 of grinding wheel [2. If it is de- I sired to predetermine the finished cylindrical or conical sizeof work thus fed against the grinding wheel, a stationary work sizing block l34 m a'y .be fixed onthe table surface 34 to be contacted by a stopscrew I40 threading crosswisethrough the carrier .leg I26 and locked in adjusted positionby nut I43. 7 p g 1 Construction of threewheel planchette carrier Figs. 3. 11, 12 and 13 show a work carrier differing from the two-wheel carrier of Figs. 1, 2 and 4'to' IQLL i'nclusive inseveral respects.- One point of difference is the elimination of the stationary fwork rest blade 13 andfthe substitution offia ,third wheel for supporting the weight of the work piece and determining the height level at tractable presser wheel.

40 which the workpiece will be rotated. Another difference is in combining in' a single wheel the functions of 'a power drive wheel and of a re- Another feature is the provision of an ejector for the work piece with which the two-wheel carrier might also be equipped. Other differences reside in placement a upstanding, carrier manipulating, steerin handleat the heel end of the carrier instead of at the toe end, and in the placementoftwo ofthe three carrier supporting legs at the heel end of the carrier while the third supporting leg is located at the toe end of the carrier nearest the grinding wheel.

Referring to the specific construction of the :carrier shown in Figs. ,11 and l2 tl le' main frame bar of the carrier is designated 91f, as in I the two-wheel planchette type ofcarrien The pointsof, difference between the two-wheel and thr e-wh e car ers r s partly in n e rangements of. shiftab'le. sections of the carrier superstructure which derive their support incommon fromjfi'ame bar 91. There is no substantial change in'the furcate guide plate I it, except that its vertical notch edge III is interchanged with its oblique or sloping notch edge H2. As in the two-wheel carrier, its support bracket 3 is clamped by screw H4 to the saddle slide I i8; fastened by a screw clamped gib like I20.

" piece adjustablyl sup orted in its post 82 and ms- Also similar in construction to the two-wheel carrier is the horizontal stop rod for the work I. tened therein by's'et screw 83. Post 82 as hereinbefore described is fastenable in chosen vertical positions on its standard 84 by clamp screw 1| while hades is ei eeie i r me es n sl d I02 which is shiftable lengthwiseofframe rial-91' best shown in Figs. 3 and 11. The supporting legs I25, I26 on cross bar I29 are fastened. to the .frame bar 97 in a location approximately beneath the work piece control wheels. The single leg I 21, instead of screwing directly into frame bar 97, screws into a slide I39 that fastens to frame bar 91' at chosen points along it length by means of a conventional gib and clamp screw.

The three-wheel carrier makes use of a rocker sub-frame I44, similar to 85 in the two-wheel carrier, similarly having a tilting base I45 like 86 in the two-wheel carrier equipped with. an adjustable stop screw 92 and lock nut 93 adapted to abut against saddle block 9| to limit the counterclockwise tilting of sub-frame I44 in Fig. 12.

Rocker frame I 44 tilts on hinge bolts 90' passing through its flanges 09'.

However, in Figs. 3, 11 and. 12, the work driving wheel I46 is carried by rocker frame I44 and thereby serves at the same time as a presser wheel since it is constantly thrust toward the left against the work piece 61 in Fig. 12 by the pull of spring 94 on the rocker arm 96 of handle 95.

In this arrangement the tubular extension 43 of the housing 44 of power transmission unit is clamped in a split bearingl l" fast to'rocker frame I44 and whose cap piece 15' is removable by loosening clamp bolts 16'.

The upper control wheel I41 of the three-wheel set functions as an axial thrust exerting wheel, whose stub shaft I48 is given bearings, which may .be of the ball or roller type, in a top bearing bracket I49 which can swivel adjustably about the axis of a clamp bolt I50 that passes through a. central clearance hole in the frame bracket I51 and threads into bearing bracket I49. When clamp bolt I50 is tightened the idler wheel I 41 is stationed bodily with its axis of rotation disposed at any chosen angle of deviation from true horizontal disposition that will cause idler wheel 41 to be skewed in such direction as to urge work piece 61 constantly endwise against the stop rod 80 during its rotation as shown in Fig. 11.

Referring now to the additional lower or third wheel of the three-wheel carrier, this may aptlybe termed the work supporting wheel I 51 whose stub shaft F58 like stub shaft I48.of idler wheel I4! is journaled in anti-frictional hearings in a lower bearing bracket I59. In the mannerof.

bearing bracket I49, bearingbracket I59 can swivel about the axis of a clamp bolt I60 passing through a clearance hole in frame bracket I'5I and threading into bearing. bracket I59. When clamp bolt I60 is tightened the work supporting.

wheel I5! is stationed bodily with its axis of rotation disposed at any chosen angle of deviation from true horizontal dispositionthat will cause the work support wheel I51 to be skewed in a direction serving constantly tourge work piece '61 endwise against the aforesaid stop rod 80.

A further feature of the three-wheel carrier, which can as well be introduced into the twowheel type of carrier, is the provision of a work a ejector I comprising an upstanding metal plate. having a shelf-like bent-over top margin underlying work piece 61. This plate is provided with two elongated slots I66 penetrated by holding screws I6! that thread into the handle arm 96.

d Slots I 66 make the work ejector I65 vertically ad-. "'lustable onhandle arm-96 so thatwhenthe lat ter is swungupward for-retracting the combined work driving and presser wheel I46 from the work piece, the work piece is lifted" away from its support wheel I5I to a more accessible position for reaching it and removing it from the carrier. Also ejector I65 prevents the work piece from dropping too low, while wheel I46 is retracted to its broken line position in Fig. 12, to permit restoration of this wheel to its full line position when urged toward the left in Fig. 12 by wheel I46.

Operation of three-wheel rail guided planchette carrier Referring particularly to Fig. 3, the threewheel planchettecarrier of Figs. 11 and 12 is shown resting upon and free to slide in a guided straight direction, that may be perpendicular to the axis of rotation of grinding wheel I2, toward and away from the abrading surface of the grinding wheel while it constrains and rotates the work piece 61. Guiding of the carrier movement is afforded by a parallel edge rail I4I against whose respectively opposite edges two of the carrier legs I26 and I2! will be held in sliding contact as the operator'shoves the carrier toward and away from the grinding wheel. For so moving the carrier a steering handle I35 is provided at the heel end of the carrier to be conveniently grasped by either hand of the operator while his other hand is left free to grasp any convenient portion of the toe endof the carrier so that the work feeding movement of the carrier will be under the joint control of both'hands of theoperator.

' This set-up of grinding machine, making use of my improved planchette carrier, is particularly suited to grinding fiat ends on rod-like or slender, spindle types of work pieces. The overall length of the finished work piece can be predetermined accurately by direct contact of toe leg I21 with stationary bafile or work sizing plate I37 that is fixed on the grinding machine table 36. Stop will be pre-adjusted to the proper distance from leg I2'I to give the desired length to the finished work piece. If desired an adjustable stop screw like I40 may project from leg I21 into contact with bafile plate I31 to permit sizing of the work piece length' by pre-adjustment of such stop screw. The fact that the work piece is being rapidly rotated simultaneously with the rotation of the grinding wheel and about an axis perpendicular to the axis of rotation of the grinding wheel will result in a perfectly flat surface being smoothly ground on the end of the work piece. The center of the work piece should be on a common. height level with the center of rotation of the grinding wheel.

' differ in any important respect from the manner of. loading the two-wheel carrier with its work piece. In both. cases the handle is lifted to retract the presser wheel I46, which in a threewheel carrier is also the work driving wheel, away from idler wheel I41'and work supporting wheel I51. With the wheel I 46 so retracted the work piece 61 can be deposited in the notch of guide plate I I0 and temporarily rest upon the ejector I65 between the control wheels. As in the twowheel carrier, the work piece will be thrust endwise into abutment with its stop 80 after which handle 95 will be permitted to drop'under' the urge of spring 94'. Thereupon, as the" work ejector I65 correspondingly drops, presserl wheel I46 will move inand constrain the work piec'efin its position shown in Fig. 12 in which-position-it trol throat of the carrier so that it can easily be reached and removed therefrom.

Construction of hinge base for work carriers Any one of the work carriers illustrated in Figs. 1, -2 and 3 may be mounted in a manner to be manually swingable about an adjustably stationed horizontal axis for plunging the work against the grinding wheel asv shown in Fig. 13. As an example the frame bar 91 in Figs. l4, l5 and 16 is shown to be seated fixedly in the groove I69 of a rockable yoke I'Eil pivotally supported on a hinge base I1I. Base I'II' may be a simple slablike block adjustably fastened on the table top 34 by clamp bolts such as I12 cooperative as usual with a T-slot 35 in table 30.

Yoke I19 is rigid and includes downward directed hinge legs I13 at its ends, each of which legs receives a pivot p n I14 longitudinally adjustable therein and fixed to the leg by set screw I15. Pins I14 are cone pointed at their innerends to seat pivotally in conical bearing holes in the edges of base I1I. 'Ihus yoke I1!) is givenadiustably tight hinged connection to base I1I so as to be rockable relatively thereto about the, common horizontal axis of pivot pins I14 in a manner to move work piece 61 toward or away from the abrasive face I3 of grinding wheel I2.

The rocking movement of yoke I'IIItoward the grinding wheel may be limited positively to an adjustable degree predetermined by-stop screw I16 threading through a bracket I11 fixed on base I'II. complished manually under finely modulated control by means of a rotary cam I18 acting on a stiff arm I19 that is adjustably fixed on yoke I by set screws I80. A spring I8I yieldingly urges arm I19 downward constantly against cam I18 whose operative peripheral contour in Fig. includes a quick lifting spiral arc I18, a slow lifting spiral arc I18" and a circular arc of dwell I19 concentric with the axis of rotation of the cam. v

The hub of cam I18 is fixed by set screw I85 on the cam shaft I96 in each of whose ends is a conical bearing hole occupied by a cone pointed bearing pin I81 similar to I14. Bearing pins I81 are fixed respective y in upstanding posts I88 made fast to base I'll by screws I90. Also it fixed on cam shaft I89 by set screw I99 is a cam operating handle I9 I. Set screws, I92 secure pins I81 in posts I88. 1

Work feeding operation of carrier on hinge base I v The following description of the manner of manually feeding work against the grinding wheel by meansof the cam handle I9! in Fig. 13 will be understood to be as fully applicable to the two-wheel carriers of Figs. 1 and 2 as to the three-wheel carrier of Fig. 3, and the frame bar 91 of all types of carriers herein disclosed may be fixedly seated interchangeably by set screws in yoke groove I69. In Fig. 13 the work piece 61 is supported by .the carrier of Figs. 11 and 12 with its axis at a level'preferably not higher than that of the center of grinding wheel I! and with its peripheral face which is to be The rock ng movement of yoke I10 is acground disposed to meetvthe abrasive face I3iof the grinding wheel when yokearm I19 is'swung" 'forrotatingthe work piece.

upward about pivot I14 to its broken line posi-'- tion in Fig. 15 and disposed to be spaced from the grinding wheel when yoke arm-occupies its full line position in Figs. 14 and 15.

The operator, as herebefore described. first lifts handle 95 to open the work receiving throat of the carrier and with the work driving presser wheel I46 thus retracted to its broken line posi tion in Fig. 12 lays work piece 61 in place with its outboard end resting in the notch of furcate guide plate I III. When handle 95 is released the work will be rotated on its own axis and biased endwise against stop and biased laterally against the straight edge III of guide plate IIII, all by the cooperative action ofthe power rotated work control wheels I46, I41 and 151. While the work piece is so rotating, the operator lifts the work feeding cam handle I 9| which turns cam I18 counter-clockwise about pivot I81 from its full line position in Figs. 14 and 15 toward its broken line position in Fig. 15. At the beginning of this movement of the cam, its "quick rise peripheral arc I18 plunges the work quickly toward and into initial contact with face I3 of the grinding wheel. Thereafter, continued turning of cam I18 causes its slowrise peripheral arc I18" to act on arm I19 and thereby to more slowly and with greater leverage force the work against the grinding wheel while it is being ground down to size. The ultimate size of the ground work piece is determined by contact-of arm I19..with the largest radius of cam I18 in the latters' circular arc of dwell I 18". The operator by means of handle I9I will hold the cam so positioned until .final sparking has died out; Stop screw I16 insures against accidentaloverthrow of the carri'erandthe work piece toward the grinding wheel. When all sparking has died out handle I9I willbe lowered and the consequent turning of cam I18 back to its full line position in Figs. 14 and 15 will be followed by rocking of yoke I10 in a clockwise direction in those figures under the urge of spring ISI. This removes the work piece I31 from contact with the grinding wheel, after which the finished work piece will be released from the control throat of the carrier and in part ejected therefrom as before explained by manually lift,-

ing handle 95.

Modifications cation of the work piece .center while the latter is capable ofiinparti'ng stronger driving torque While for simplicity of illustration the wor piece-referredto in the foregoing has been shown and described as an integral rod like spindle of relatively lon and slender proportions, the present invention may be practiced and its advantages availed'of in the grinding of work pieces that are very short in axial extent and of work piecesithat are diametrically larger or smaller than the work piece 61 shown in the drawings.

The relative directions of rotation of the rod 51 and of the grinding .wheel I2 may be selected at the choice'of the operator depending on the kindof grinding operation it is desired to perform- The materials. of which 4| and 12 or wheels 16.5, 141 and. [51 may be made will depend on which, of these. wheels are. to impart rotary torque to rod 67-. Hard rubber or composition materials having a, surface ofhigh frictional properties may be. preferable for the driving wheels. The other or prop wheel or wheels may be of metal as hard as the. rod or tube. 61 and polished for perfect surface smoothness.

These are but instances of many varieties of construction that may be resorted to for seizing upon the. novel principles underlying the invention wherefore the. fOlIOWiIlg claims are directed to. and intended to cover all substitutes and equivalents for the specific constructions herein disclosed that come fairly within the. definitions of the claims.

I claim:

is A centerless grinder, comprising a base, a.

said slide adjacent said work supporting rolls, a

work driving r011 mounted in the frame for movement toward and away from said work supporting rolls in an approximately horizontal direction for gripping a. work piece therebetween at three, circumferentially spaced points, drive means. for driving said work driving roll, and means for 'yieldingly urging said work driving roll toward said work supporting rolls.

' 2. The-method of centerless, grinding by means of a. fast moving abrasive surface which comprises, pressing in radially opposed directions .upon the circular periphery of an axially elongated round work piece at respectively different pressure points therealong that are relatively disaligned in. an axial direction with a roller force of sufiicient frictional cling to rotate the work piece about an axis encompassed by its own peripherythereby to urge said axis of the rotating work, piece in a swinging direction, and nesting against relatively fixed supporting surfaces of a.

stationary constraining abutment at least two circumferential points in the periphery of a different section of the length of the rotating Work piece axially spaced from said pressure points, and presenting into abrading contact with said fast moving abrasive surface the revolving periphery of a still different section of the length of said work piece axially displaced from all of said points.

3. The method of centerless grinding in pattern guided relation to a fast moving abrasive surface which comprises, pressing in radially opposed directions upon the circular periphery of an axially elongated round work piece at respectively fd'ifferent pressure points therealong that are relatively disaligned-in an axial direction with the aid of a roller force of suflicient frictional cling to rotate the work piece about an axis encompassed by its own periphery thereby to urge said axis of the rotating work piece in a swinging direction, nesting against relatively fixed supporting surfaces of a stationary constraining abutment at least two circumferential points. in the periphery 'jof' a different. section of the length of the rotating work piece axially spaced from said pressure points, presenting into abrading contact with .said fast moving abrasive surface the revolving periphery of a still different section of the length .of said work piece axially isplaced from all of said points, and conveying .said rotating supportingly nested work piece. bodily in pattern guided relation to the fast moving abrasive s urface. 1 Q4. The. method of centerless grinding by means of a fast. moving abrasive surface. which coniprises, pressing in radially opposed directions upon the circular periphery of an axially elongated round work piece at pressure points sufficiently offset lengthwise thereof to urge the axis of the work piece in a swinging direction with the aid of a roller force of sufiicient frictional cling to rotate the work piece about an axis encompassed by its own periphery said force being directed at. sufiicient obliquity to said axis to urge the. work piece in a lengthwise direction, nesting against relatively fixed supporting surfaces of a stationary constraining abutment at least two circumferential points in the periphery of a different section of; the. length of the rotating work piece axially spaced from said pressure points, and presenting into abrading contact with said fast moving abrasive surface the revolving periphery of a still different section of the length of said work piece axially displaced from all of said points.

5, In a grinding machine having a fast moving abrasive surface, a maneuverable carrier affording centerless support and constraint for an elongated work piece of circular periphery while the work piece is conveyed and rotated by said carrier with respect to said abrasive surface, comprising the combination of, a carrier frame pivotally mounted on said machine for swinging movement about a vertical axis relative to said abrasivev surface; a set of roller Wheels rotatably 3 mounted on said carrier frame arranged for simultaneous rolling contact with horizontally opleast one of which wheels is a driving wheel having a surface of suflicient frictional properties to rotate the work piece, a stationary support below the horizontal level of peripheral contact of said wheels with the work pieceunderlying and thereby adapted to bear the entire weight of the work piece in a manner to determine the level at which the work piece will be maintained While being rotated by said wheels, a source of power supported apart from said carrier frame, and mechanical means operatively coupled to said driving wheel arranged to transmit power thereto from said source during bodily movement of said carrier frame.

6. In a grinding machine having a fast moving abrasive surface, a maneuverable carrier aifording centerless support and constraint for an elongated work piece of circular periphery while the work piece is conveyed and rotated by said carrier with respect to said abrasive surface, comprising the combination of, a carrier frame pivotally surface, a set of roller wheels rotatably mounted on said carrier frame arranged for simultaneous rolling contactwith horizontally opposite sides of the periphery of the work piece at least one of which wheels is a driving wheel having a surface of sufiicient frictional properties to rotat the work piece, a stationary support below the horizontal level of, peripheral contact of said wheels with the work piece underlying and thereby adapted to bear the entire weight of th work piece in a manner to determine the level at which the work piece will be maintained while being rotated by said wheels. a source of power supwported apart from said carrier frame, and mechanical means operatively coupled to said driving wheel arranged to transmit power thereto from said source during bodily movement of said carrier frame. V.

7. Centerless grinding apparatus for bodily maneuvering an elongated circular work piece in relation to the power driven abrasive surf-ace of a grinding machine while peripherally supporting and rotating such work piece without assistance from said abrasive surface, comprising in combination with the abrasive surface of the grinding machine, a stationary grinding machine frame, a work carrier supported by said frame in a manner to be movable bodily in relation to said abrasive surface, a set of wheels rotatably mounted on said work carrier arranged for peripheral rolling contact simultaneously with horizontally opposite sides of the. circular work piece, at least one of said wheels being power driven, a stationary support belowthe horizontal level of peripheral contact of said wheels with the work piece constructed and arranged to underlie and bear the entire weightof the work piece in a manner to determine the level at which the work piece will be maintained while rotated by said wheels, an upright stop surface fixed on said stationary frame of the grinding machine, and a pattern toe carried by and projecting from said work carrier having a convex contour adapted to rock against said stop surface in a manner restricting the approach of said carrier toward said abrasive surface.

8. In a grinding machine including a fast moving abrasive surf-ace, apparatus affording centerless support and constraint for an elongated work piece of circular periphery while the work piece is rotated with respect to said abrasive surface without propping thereby, comprising in combination with said abrasive surface, plural rotors arranged for simultaneous rolling contact with the periphery of the work piece atopposite sides thereof and at points relatively offset axially of the work piece thereby to impart to the rotating work piece a bias tending to cause swinging of the latters lengthin a lateral direction, and a stationary abutment displaced from said rotors axially of the Work piece having a constraining face arranged to opposeand-limit said swinging of the rotating work piece in said direction thereby to establish fixity of the axis of the rotat ing work piece.

9. In a grinding machine having a fast moving abrasive surface, a maneuverable carrier affording rolling support and constraint for an elongated work piece of circular periphery while the work piece is conveyed and rotated by said carrier with respect tosa'id abrasivesurface, comprising the combination of, a carrier frame supportable on said machine for free-roving movement relative thereto in random directions at will relative to said abrasive surface, a set of rotors arranged for simultaneous rolling contact with the periphery of the work piece at least one of which rotors is a work-driving wheel, a bearing in which one of said rotors is rotatably supported, structure supporting said bearing movably on said freeroving frame in a manner to convey one of said work contacting rotors toward and away from the Work piece, a source of power supported apart from said carrier frame, and a flexible shaft connected to said source of power and extending from a relatively high level downward into operatively coupled relationship to one of said wheels thereby to transmit power to the latter from said 18 source of power, said flexible shaft being long enough to trail and permit free bodily movement of said carrier frame into an unlimited variety of positions of said carrier relative to said abrasive surface.

10. In a grinding machine having a fast moving abrasive surface, a maneuver-able carrier affording rolling support and constraint for an elongated Work piece of circular periphery while the work piece is conveyed and rotated by said carrier with respect to said abrasive surface, comprising the combination of, a carrier frame supportable on said machine for bodily movement relative to said abrasive surface, a set of rotors. including at least two roller wheels at least one of which is a work-driving rotor and includes a wheel surface of sufficient frictional properties to rotate the work piece said roller wheels being rotatably mounted on said carrier frame and arranged for simultaneous rolling contact with the periphery of the work piece, a bearing on said frame in which one of said wheels is rotatably supported, a source of power supported apart from said carrier frame, and a flexible shaft operatively coupled to one of said Wheels and arranged to transmit power thereto from said source of power while permitting free bodily movement of said carrier frame, together with a stationary work support underlying a gap between said wheels in a position to limit the depth to which the said work piece can sink while being rotated in rolling contact with said Wheels.

11. In a grinding machine having a fast moving abrasive surface, a maneuverable carrier affording rolling support and constraint for an elongated work piece of circular periphery while the work piece is conveyed and rotated by the carrier with respect to the abrasive surface, comprising the combination of, a carrier frame supportable on said machine for bodily movement relative to said abrasive surface, a set of rotors comprising at least three roller wheels arranged for simultaneous rolling contact with the periphery of the work piece at least one of which wheels has a surface of sufficient frictional properties to rotate the work piece and at least one of which wheels sufficiently underlies a gap between two others of the wheels to limit thereby the depth to which the work piece can sink while being rotated in rolling contact with all of said wheels, three hearings on said carrier frame in which said three wheels are respectively journaled, connections constructed and arranged to permit at least two of said rotors to be shifted to selected degrees of skewed disposition relative to each other and to said, third wheel, a source of power supported apart from said carrier frame, and a flexible shaft operatively coupled to one of said wheels and arranged to transmit power thereto from said source of power while permitting free bodily movement of said carrier frame.

12. In a grinding machine having a fast moving abrasive surface, a maneuverable carrier affording rolling support and constraint for an elongated work piece of circular periphery while the work piece is conveyed and rotated by said carrier with respect to said abrasive surface, comprising the combination of, a carrier frame supportable on said machine for bodily movement relative to said abrasive surface, a set of rotors rotatably mounted on said carrier frame arranged for simultaneous rollingcontact with the periphery of the work piece at least one of which is a work driving rotor and includes a wheel suracademia face of sufficient frictional proper-ties to rotate the work piece, a bearing on said frame in which said work driving rotor is rotatably supported, a source of power supported apart from said car: rier frame, a flexibl shaft operatively coupled to said driving wheel arranged to transmit power thereto from said source of power while permitting free bodily roving movement of said carrier frame, a stationary abutment face shaped and arranged on said carrier frame to engage a pore tion of said rotating work piece that projects in outboard relation to its locus of rolling contact with said roller wheels in a manner to limit move. ment thereof in at least one lateral direction, the respective points of rolling .contact .of said wheels withsaid work piece .being relatively .ofiset lengthwise of the work piece in a manner to ime part to the latter a bias tending to. swing said work piece portion in saidlateral direction to, ward said abutment face, and a rotary bearin supporting at least one of said rotors movably mounted on said carrier frame in .a manner to permit shifting of the rotor in directions toward and away fr m nother of said rotor thereby to press said shiftable roller against or retract it from a work piece lying between the wheels.

13. In a grinding machine including a fast mov g bras u f e apparatus aff rd n centerless support and constraint for an elonsa or i ce i ircu a r e h le the work piece is rotated with respect to said abrasive surface without propping thereby, comprising in combination withsaid abrasive surface, plural ro'.ors arranged for simultaneous rolling contact with the periphery of the workpiece at opposite sides thereof and at points relatively offset axially of the work piece thereby to impart to the rotating work piece a bias tending tocause swinging of the latters length in a lateral direction, and a stationary abutment displaced from said rotors axially of the work piece having a constraining face arranged to oppose and limit said Swinging of the rotating work piece in said direction thereby to establish directional alignment of the axis of the rotating work piece, said abutment comprising a furcate rest of size "and shape to permit rotary nesting therein of a portion of the rotating work piece that projects in outboard relation to its said points of rolling contact with said rotors.

14. In a grinding machine including a fast moving abrasive surface, apparatus affording centerless support and constraint for an elongated work piece of circular periphery whilethe work piece is rotated with respect to said abrasive surface without propping thereby, comprising in combination withsaid abrasive surface, plural rotors arranged for simultaneous rolling contact with the periphery of the work piece at opposite sides thereof and at points relatively ofEset axially of the work piece thereby to ini= part to the rotating work piece a bias tending to cause swinging of the latterfs length in a lateral direction, a stationary abutment displaced from said rotors axially of the work piece having a constraining face arranged to oppose and limit :said swinging of the rotating work piece in said .direc-.- tion thereby to establish directional alignment of the axis of the rotating work piece, and .a stop stationed in a position to contact with an end of the work piece at the opposite side of said rotors from said abutment.

15. In a grinding machine including a fast moving abrasive surface, apparatus affording centerless support and constraint for an elongated work piece of circular periphery while the work piece is rotated with respect to said abrasive surface without propping thereby, comprising in combination with said abrasive surface,-plural rotors arranged for simultaneous .rolling contact with the periphery of the work piece at opposite sides thereof and-at points relatively offset axially of the work piece thereby to impart to the rotating work piece a bias tending to cause swinging of the latters length in a lateral direction, at least one of said rotors being skewed in a manner to thrust t e Work piece longitudinally ina direction away from said abrasive surface while rolling in contact with the work piece, a stationar abutment displaced from said rotors axially of the work piece having a constraining face arranged to oppose and limit said-swingin of the rotating work piece in said direction thereby to abl h di eaional al nment of e axis of t e r a ng ork. pie e and a s op s a d in a position to contact an end of the work .piece and to oppose th longitudinally directed thrust thereupon of said skewed rotor.

WILLIAM HORBERG. REFERENCES CITED The following referencesare of record in the file of h s nt UNITED STATES PATENTS Number Name Date 1452;03 Hervig in, A r; 24, 1923 1,590,190 Helm June 29, 1926 1,733,99 Kl h ai Oct. 22 1929 1,803,984 van Norman ;Ma 5, 1931 1,314,361 Booth mania- Jun 14, 1931 12,264,179 Johnson 'Nov. 25,1941 2 6 305 After M. n. 13, 1942 2,331,3 1 .Ekstedt 'Oct. .12, 1943 2,411,972 Melin Dec. 3, 19.46,

FOREIGN PATENTS Number Country Date 394,472 Germany w i Apr. 17, 1924 

